He said he doesn't want isolation, so that pretty much excludes IEMs. While some IEMs like the M31 and Panasonic RP-HJE450 are ported, they still isolate somewhat. For less isolation, get traditional earbuds like the Sennheiser MX880 or MX580, or Yuin PK2 or PK3. The traditional earbuds don't have such great bass though. The RPHJE450 has plenty of bass.